Trump tweeted about the Russia investigation and the travel ban as the White House sent an ominous warning to Syria

While the White House issued a surprise warning to Syria on Monday alleging the regime of Bashar Assad was preparing a "potential" chemical-weapons attack, President Donald Trump was tweeting about the Russia investigation and the travel ban.

"From @FoxNews "Bombshell: In 2016, Obama dismissed idea that anyone could rig an American election." Check out his statement - Witch Hunt," Trump tweeted, shortly after the White House released its statement on Syria.

Trump appeared to be referencing a Washington Post report that painted a timeline of Obama's actions surrounding Russia's interference in the 2016 US election.

Minutes after his first tweet, Trump sent another to tout the US Supreme Court's decision to lift several injunctions on his travel ban: "Great day for America's future Security and Safety, courtesy of the U.S. Supreme Court. I will keep fighting for the American people, & WIN!"

Critics said Trump's off-topic musings, sent as the White House and defense officials coordinated an ominous public warning to an enemy state, were seen as poorly timed.

"He's very undisciplined," said Jim Jeffrey, former US ambassador to Turkey and Iraq, in a Politico report. "He does this all the time."